Alzheimer's disease is the most common neurodegenerative disorder and is characterized clinically by cognitive dysfunction and pathologically by the formation of extracellular amyloid plaques and intraneuronal deposition of aggregated tau into neurofibrillary tangles. Although rare forms of the disorder are caused by highly penetrant mutations in autosomal dominant genes, the pathogenesis of more common forms of the disease remains incompletely understood. A thorough understanding of the basic mechanisms driving loss of neuronal integrity during aging would provide a crucial underpinning for efforts focused on identifying the pathways mediating neurodegeneration in Alzheimer's disease and related disorders. Thus, to provide a comprehensive knowledge of mechanisms driving brain degeneration in higher eukaryotes we will take advantage of the power of forward genetics in Drosophila to outline, in an unbiased fashion, mechanisms controlling preservation of neuronal function during aging. Then, to relate our findings to human disease directly we will integrate, using a systems biology approach, networks derived from eQTL analysis and RNA sequencing data from a unique and high-quality resource of laser captured temporal neurons from patients with Alzheimer's disease and carefully age- and sex-matched control patients without neurological disease. We will further discover pathways relevant to disease by performing an integrated metabolomics and phosphoproteomic analysis in Drosophila models relevant to Alzheimer's disease, namely human tau and A transgenic animals. The resulting networks, including previously undiscovered, or hidden, nodes will be tested for their causal relationship to neurodegeneration in Drosophila in well-characterized models of tau and A neurotoxicity. Our studies will thus discover on a genome scale novel mechanisms driving neurodegeneration and will provide a census of those mechanisms most likely to underlie cell death in Alzheimer's disease and related disorders. The genes and pathways we discover can then be examined in mechanistic detail in the appropriate mammalian models.